The NetHack Object Identification Spoiler

This spoiler details techniques for identifying objects in the face
of a shortage of identify scrolls; it's actually possible to sort out
nearly every object in the game without risk of adverse
consequences. I am keen to have submissions on additional methods of
identifying objects, or corrections to any errors in this spoiler. I
am not keen to be told that I use British English spellings; you
wouldn't think I'd have to mention that, but unfortunately that is not
the case. I deal only with vanilla NetHack, but the techniques will be
useful in variants.

This spoiler is really long; you have been warned. You may freely
distribute and modify this spoiler under the terms of the GNU General
Public License. It is by no means all my own work; I must acknowledge
assistance (in no particular order) from Dylan O'Donnell, Klaus
Kassner, David Goldfarb, Raisse, Zack Weinberg, Kathrin Paschen,
Michael Hedera, Eva Myers, Rob Elwood, Kate Nepveu, Marisa Lohr,
Gregory Bond, "Chris", Jaakko Salomaa, Kieron Dunbar, Dan Sheppard,
Tina Hall, George Fleming, Ian Jackson, Lotta Loytonen, Topi Linkala,
Jukka Lahtinen, David Throop, Keith Hearn, Trebor Rude, Colin Watson,
Seraphim, Wes Irby, Jakob Creutzig, a mystery contributor, and no
doubt one or two I've forgotten (sorry).

Contents

If you do have some identify scrolls, you should always bless
them and ensure you have as many unidentified objects in your
inventory as possible before reading them; there is a one in five
chance that a blessed scroll will identify everything in your main
inventory.

It is vital that you understand the use of the #name command;
either to name a specific object (this particular potion is uncursed)
or a class of objects (these scrolls cost 50 zorkmids in shops.) #name
is also useful to sort out objects with identical appearances; if you
#name the first kind of lamp you find 'lamp 1' and then find an
unnamed lamp, you know one of the two kinds is magic, or if you #name
a red gem 'red gem 1' and find an unnamed red gem, they can't both be
worthless glass. Where the object has not been completely IDed it is
best to include the appearance in the name; for example, if a scroll
type is named "READ ME costs 100" it can be distinguished from a
second scroll type named "YLOH costs 100", or if a wand is named
"uranium vanisher" it can be distinguished from a second wand named
"iron vanisher". It's worth noting that you can blot out an existing
name by #naming the object to ' ' - this is extremely important
because when you have a vague name for an object (like "orange costs
100") and want to actually try one out, you'll only get the 'call'
prompt if it's unnamed; and that when the game asks a question like
"Call an orange potion?" that's equivalent to #naming it.

An awareness of item probabilities helps; if you find six of
'lamp 1' and one of 'lamp 2', it's not hard to guess which is
magic.

A lot of techniques demand that you know the
blessed/uncursed/cursed (henceforth "b/u/c") status of an object, or
at any rate that it's not cursed. Dropping items on altars works (or
being a Priest), but your pet will not walk on a cursed object (unless
you displace it, there's food there, or it "moves only reluctantly");
if you leave your pet behind, I've no sympathy. Watching monsters use
weapons and take off armour is also instructive; cursed wielded
weapons are noticed as such (if you see the monster actually wield
it), any item (including potions) that 'slips' or 'misfires' as a
monster throws or fires it is cursed (but a cursed item will not
always slip), and any armour a monster removes is not cursed.

Some objects are always generated uncursed (otherwise, objects are
usually uncursed, but sometimes blessed or cursed with roughly equal
probability, unless noted otherwise): non-tin food; gems other than
loadstones; tools other than light sources, grease, crystal balls and
figurines; armour and weapons with positive enchantments (may be
blessed); statues and boulders. But beware bones piles, where all bets
are off. There are also some mentions of messages from cursed items,
in case you really do have no way of determining b/u/c status.

Some objects give you the message "You have a strange feeling
for a moment, then it passes" if flags.beginner is set; roughly
speaking, this is the case if you have never had more than 500 XP
(250 for wizards). If you don't have showexp on, a level 6 Wizard
or a level 7 anything qualifies, provided you have not gained XP
from potions of gain level, wraith corpses, or sex (which don't
count). This is important because you cannot always distinguish
objects when this happens.

Some objects can be identified if you zap a wand (or drink a
potion) of enlightenment while wearing/carrying them, but the
possibilities there are too great to number - for instance, one can
distinguish flint stones and luckstones, but this technique is most
useful on uncursed rings and amulets.

There are some guaranteed objects at various points in the
dungeon. Primary amongst these are the gem piles in the Gnomish Mines
and in Fort Ludious (see 'Gems' below); the
'statue of a knight named Perseus' on the Medusa's level, which may
contain a cursed shield of reflection, levitation boots, a blessed +2
scimitar, and/or a sack; the top level of Sokoban contains either an
amulet of reflection or a bag of holding (on the space marked
"Elbereth"), and the two scrolls found in the bottom left corner of the
bottom level are always scrolls of earth; Vlad's Tower contains an
amulet of life saving, amulet of strangulation, water walking boots,
crystal plate mail, and a spellbook of invisibility on the middle
level, and a long sword, lock pick, elven cloak and blindfold on the
bottom level; Orcus always carries a wand of death; and the Wizard
will bring a spellbook of dig to the Plane of Earth.

The most basic technique for a lot of classes of objects is
grouping by price in shops. Everyone knows that identify scrolls
are the cheapest (don't they?); but a lot of other objects can be
reduced to two or three possibilities by price grouping. This
technique is useful for things like potions and scrolls, where you
want to know (say) what scrolls marked ELAM EBOW are; less useful
for things like weapons where you know what long swords are but you
want to know what this particular long sword is. Hence, I'm going
to open with a discussion of how the sale or purchase price of an
object is determined from the base price - the cost listed in
objects.c. You may also want to examine the 'shopping'
spoiler.

For most objects, the price is the base price multiplied by a
few fiddle factors for things like Charisma. First, though, the
base price is hacked about for a few things. If you're hungry, food
is much more expensive (but you don't need to price group food
items.) An empty unrechargeable (possibly cancelled) wand is
worthless (but if you're buying, the base price of a 'worthless'
object is 5 zorkmids); so is an uncursed potion of water (always a
'clear potion', so easy to identify.) The base price of armour and
weapons is increased by ten zorkmids for every point of positive
enchantment. Used candles are worth less, but identifying candles
isn't really important. Unidentified gems are cheap if selling or
pricey if buying; the details have been relegated to the gems section.

If you're buying, one in four objects (based on the object ID
number, so consistently for a given object) has its price increased
by a third. This is awkward and nearly unavoidable, especially if
it prevents you distinguishing an object with a base price of (say)
60 from one with a base price of 80. Where base prices are so
positioned, you may need to see several objects of a given type
before you can determine what's really going on; since this is the
only surcharge that's unpredictable and applies to some but not all
objects of a given type, references to being fooled by the
surcharge refer to this one.

If there is a second object of the same type in the shop, but
only one is surcharged, and they stack, I am told you can get both
at the lower price by dropping the cheap one on the expensive one
and picking them up again, not that this really pertains to
identification.

A dunce cap, a visible shirt (no body armour or cloak) or being
a tourist of level 14 or less carries a surcharge of another third,
as does an angry shopkeeper (but then you may be more concerned
with not dying.)

If you're selling, the base price is first of all divided by two -
three if you're a low-level tourist, wearing a visible shirt or a
dunce. 1/4 of sales (at random) have the price reduced by 1/4, but
(unlike the random purchase surcharge) you can circumvent this by
getting 2-3 quotes on the same object. Sale prices are also not
influenced by Charisma, making identification of an object's price
group much easier when selling - of course, if you can afford to buy
an object, you can do so and get a sale quote immediately afterwards;
and if you don't have an object of your own to get sale quotes on,
IDing is of less interest (although you might find one later,
obviously, and want to use it without returning to the shop; or simply
be planning to rob the shop in a way that angers the shopkeeper).

A shopkeeper who has insufficient cash will offer 'only n gold
pieces' for an object (where 'n' is all the gold he has); clearly
this limits the deduction possible about the sale price. However, a
shopkeeper with no gold at all will offer credit equal to 90% of
the sale price (as ever, the surcharge may apply), which is just as
good.

It is worth noting that throwing an object into a shop makes it
the shopkeeper's (as does killing a monster that drops it, greasy
fingers, etc.), and even if the object is not one normally sold in
that shop, you can now get a purchase quote for it. Of course, this
is expensive.

Here's a table of some common base prices and the effective
purchase prices. There are two rows of Charisma scores; one for prices
where no surcharge applies and one for a price with one surcharge; you
then find two prices below, one surcharged and one not. Why like that?
So you can locate your Charisma score (in the second row, if you have
an unavoidable surcharge) and simply look down the two columns to find
all possible prices. Sale prices are equal to the purchase prices for
a Cha 19+ with no surcharge. There are probably some rounding
errors; sorry.

Cha (no surcharge)

3-5

6-7

8-10

11-15

16-17

18

19+ or sale

19+

Base Price (down)

Cha (with sur)

3-5

6-7

8-10

11-15

16-17

18

19+

20

53

70

40

53

35

46

30

40

26

34

20

26

17

22

15

20

13

17

10

13

50

133

177

100

133

88

117

75

100

66

88

50

66

44

58

37

49

33

44

25

33

60

160

213

120

160

106

141

90

120

80

106

60

80

53

70

45

60

40

53

30

40

80

213

284

160

213

142

189

120

160

106

141

80

106

71

94

60

80

53

70

40

53

100

266

354

200

266

177

236

150

200

133

177

100

133

88

117

75

100

66

88

50

66

150

400

533

300

400

266

354

225

300

200

266

150

200

133

177

112

149

100

133

75

100

175

466

621

350

466

311

414

262

349

233

310

175

233

155

206

131

174

116

154

87

116

200

533

710

400

533

355

473

300

400

266

354

200

266

177

236

150

200

133

177

100

133

250

666

888

500

666

444

592

375

500

333

444

250

333

222

296

187

249

166

221

125

166

300

800

1066

600

800

533

710

450

600

400

533

300

400

266

354

225

300

200

266

150

200

400

1066

1421

800

1066

711

948

600

800

533

710

400

533

355

473

300

400

266

354

200

266

500

1333

1777

1000

1333

888

1184

750

1000

666

888

500

666

444

592

375

500

333

444

250

333

600

1600

2133

1200

1600

1066

1421

900

1200

800

1066

600

800

533

710

450

600

400

533

300

400

700

1866

2488

1400

1866

1244

1658

1050

1400

933

1244

700

933

622

829

525

700

466

621

350

466

Now, onto some sorts of objects;

Potions

Potions can be identified in several ways, not least because
monsters tend to use them; once you have somehow found some of the
more harmful ones, you can just drink the (non-cursed) things,
especially if you have a unicorn horn available and/or have done
some price grouping - but even without price grouping you can
probably start quaffing eventually.

Clear potions are water, but you knew that, right? No other potions
have a fixed description, but using the (a)pply command will only
present potions of oil as potential targets for the command, so they
can also be easily identified.

The special functions of smoky and milky potions (djinn and
ghosts) are not related to what type they are, but it is worth
saving and blessing smoky potions regardless of whether they are a
type you would normally drink.

Dipping a missile weapon (arrow, crossbow bolt, &c.) into a
potion of sickness will poison it (and now you know what the potion
is; it 'forms a coating' on the weapon). Dipping anything into
polymorph polymorphs it. It's a smart plan to test potions that
might be polymorph with a missile weapon, unless you have a spare
unicorn horn; and it's a cheap way to ID sickness before you have a
unicorn horn at all. Don't #name them before making this test; polymorph
IDs itself, and sickness will prompt for a name.

If you have a unicorn horn, #dipping it into potions of
hallucination, blindness or confusion will turn them to water, and
turn potions of sickness to fruit juice (which is one way to
distinguish fruit juice and see invisible.) Unless you want to keep
potions of confusion for use before you wear out a spell, this is a
very valuable tactic; #name all potions 'harmful <colour>'
and dip a unicorn horn into them; if they don't clear or go a new
colour, #name them back (if they go a new colour, #name them 'fruit
juice', obviously.) The gotcha here is that you can't identify
paralysis or sleeping like this, so you can't get rid of all
massively harmful potions; however, Eva Myers points out (amongst
other things) that a ring of free action negates the harmful
effects of either, but they are still identified.

If you have an amethyst (easy to find if an archaeologist, or if
you have three violet gems with different #names - one is
worthless, one is fluorite, one is amethyst), it will turn booze
into fruit juice.

Monsters may drink the following types of potions; healing,
extra healing, full healing, gain level, invisibility, speed,
polymorph. Pestilence may drink potions of sickness, but that's
kind of obscure. Nearly all these cases identify the potion for
you; the only exception is cursed gain level ("<monster>
rises up, through the ceiling!"), where you are called upon to
supply a name.

Monsters also throw paralysis, blindness, confusion, sleeping
and acid. Paralysis, sleeping and blindness identify themselves;
confusion ("You feel somewhat dizzy.") and acid ("This burns!") ask
you to supply a name. There are some cases where a monster might
throw a potion that hits another monster; my reading of the source
is that you are not called upon to supply a name (unless you
breathe the vapour), but if you can guess it right and have another
sample in your inventory you could #name that (even if you can't
guess, it must be one of those five, so can be #named "thrower" or
whatever.)

In theory you could go chucking unided potions at monsters to
see what they do, but that is normally pretty daft (or dangerous,
in some cases, especially polymorph.)

There are guaranteed to be six potions of booze in the Gnome King's
Wine Cellar, so if you get that mine ending you can effectively
eliminate booze from consideration; also the southernmost pile will
contain a potion of object detection (and only that), which is handy
if you haven't killed a lot of nymphs yet. (The Gems section discusses which mine ending is which,
but providing layouts is beyond the scope of this spoiler). There is
always an amethyst in any mine ending, so a little work with violet
gems lets you write off fruit juice, too.

Nymphs often (one in two) have potions of object detection, but
they also can have other random potions. Shopkeepers often have
healing and extra healing (in their own inventories, not their
shops.)

A delicatessen stocks and buys only potions of fruit juice,
booze, and water (but, like any shop, will sell any item that
happens to land in it - thrown in, dropped by a dying monster, or
whatever.)

Now, by price group;

5 - uncursed water. It's clear, anyway, but this
lets you know which of your potions of water are uncursed. If you
really have no altars, you can sort your potions of water into three
groups (which will refuse to merge in inventory); having eliminated
uncursed by price or probabilities, you can dip a useless object (or
see below) into one of the other two stacks and see what happens to
it, to determine which stack is holy water. This makes it more
practical to head for Sokoban before Mine Town.

It's best to dip a cursed useful object if you have one. If you
picked unholy water, nothing happens ("Interesting..."); if you
picked holy water, you were going to use it up uncursing that
object anyway. Hence, you avoid a wasted potion.

50 - see invisible, booze, sickness, fruit
juice.

The presence of sickness in this one is a bit of a nuisance,
since monsters won't identify it for you, but testing with missile
weapons makes it easy enough to sort out. Blessed sickness does
nothing, so blessed potions in this group are safe; healers are
immune in any case; if the damage won't kill you, a ring of sustain
ability will prevent the stat loss, or you might know and have a
stock of restore ability - or you might have started with a potion
of sickness.

It's worth noting that non-cursed see invisible (but not fruit
juice) will unblind you if you are blind, which may help to pick
them apart if there isn't something invisible about.

If the potion is cursed, fruit juice and see invisible both say
"Yech! This tastes rotten." Booze makes you pass out; sickness does
more damage.

Note, above, that a deli helps you sort this lot out - not just
by what it sells, but by what it buys.

Sleeping and confusion are quite irritating, but can usually be
safely drunk in a locked room. Hallucination is the real stinker
here, without a unicorn horn - also, the monsters won't sort that
one out for you. Whether it's worth going through all that to find
restore ability by elimination is up to you, but if you're really
hurting for it, go ahead. Restore ability, which does not auto-ID,
will make you feel 'great', 'good', or 'mediocre', but never
'tastes' of anything.

Once you've had blindness thrown at you or unicorn-horned it out
or have a means of curing it (and have a mummy wrapping, if
planning to shop), go ahead with this group, if uncursed. Cursed
invisibility gives you aggravate monster - also, you can't identify
it if you're already invisible, so you may need to see a monster
drink it.

Monster detection; it's wise to check there's a monster around
if flags.beginner is set, since otherwise you won't ID it for sure;
if you're not a beginner, "You feel threatened." (or "You feel
lonely", if blessed).

Cursed gain energy makes you feel "lackluster", but is still
identified.

Also, annoyingly, if you get surcharged buying these potions,
they look like the ones in the next group.

200 - speed, levitation, enlightenment, full healing,
polymorph.

Without polycontrol polymorph is likely to make your life
miserable regardless of b/u/c status. If you must try potions in
this group, do it without shirts, body armour or cloaks in a locked
room, on a level with a sink (which eases the effects of unblessed
levitation; cursed levitation causes you to hit your head on the
ceiling but is no worse than uncursed thereafter). Enlightenment
and full healing can be identified even if cursed (enlightenment
makes you feel "uneasy"); speed will normally be identified for
you, but a non-cursed speed will heal wounded legs and need to be
#named 'speed', or if you are already very fast your legs will 'get
new energy' (but no auto-ID.)

250 - acid, oil.

Since you can use the (a)pply trick to identify oil, weeding out
acid is also trivial once you can price-ID. Acid "explodes" when
immersed in a pool or moat, but since this would possibly destroy
other potions this is only useful after an accident, if you can
remember what you had beforehand...

300 - gain ability, paralysis, gain level.

This group's quite tricky, and often better left. Gain ability
is a bit wasted if not blessed ("tastes foul", if cursed); gain
level is wasted at low levels, or if cursed, or if unblessed at
intermediate levels; and paralysis is nasty, blessed or cursed.
Once you've got paralysis out the way (by having it thrown at
you?), it's probably worth hanging onto the others to bless
them.

Scrolls.

Scrolls are trickier than potions; monsters don't use so many of
them, and amnesia will always ruin your day, so there's nothing
much to be done but identify scrolls that might be amnesia.
Sufficiently lucky wizards with magic markers and a stock of blanks
can always try writing the scrolls they are most worried about (as can
any class, but with only a 1/3 chance with maximised Luck, so you'd
need a large surplus of marker charges for this to be sensible).

A scroll by itself in a one-space corridor 'closet' in the wall
is practically always teleportation (and, if there are multiple
scrolls, one of them is practically always teleportation), as is a
scroll in a corridor next to a room in general.

Like clear potions, an unlabelled scroll is always blank, but
can be read (and not consumed) to identify it. But who cares?

Monsters may use scrolls of teleportation, create monster, fire
and earth, but the latter two are quite unlikely.

Conversely, the fact that many scrolls have different effects
while confused can let you weed out some of the harmful ones
relatively unscathed.

The fact that scrolls of scare monster will crumble to dust when
picked up, if cursed, and go one step towards cursed otherwise,
makes them easy to spot - but if you are in a shop and you are
really broke, you may want to take care to get scroll prices via
#chat.

As mentioned earlier, there are always two scrolls of earth on
adjacent squares in the lower left corner of the first level of Sokoban.

Now, by price group;

0 - mail.

Enough said.

20 - identify.

This one is easy; it's also very common - with twice the item
probability of the next most common scroll, although the various
special cases that create teleportation probably mean it is created
still more frequently. If you really don't have any suitable shops,
accumulating a vast mass of scrolls and reading the common ones may
be the only thing to do.

50 - light.

Also unique in cost and auto-identifying when read; but, unlike
identify, largely useless and a prime candidate for blanking.

60 - enchant weapon, blank.

This group would be easy if a surcharge didn't make it look like
one of the next group. If you don't know the b/u/c status, you could
get confused and read it while using unrustproof (or fireproof) weapon
and armour; cursed confused enchant weapon removes rustproofing, but
there will be none to remove. However, if it's blessed remove curse
it'll still ruin your day. Another approach would be to try unconfused
with expendable armour and weapon - if you can uncurse things affected
by remove curse.

80 - enchant armour, remove curse.

These are not so easy unless you know the b/u/c status, because
a confused remove curse randomly curses or blesses some of the
objects it would otherwise have operated on. Oddly enough, that
means (if you are wearing no rustproof armour) that cursed confused
is safe; remove curse just "disintegrates".

The presence of fire and destroy armour in this group make it
harder than it might be. If you're fire resistant or can take the
damage and don't have any flammable objects, fire's OK; destroy
armour can be handled by not wearing any armour (but you get a
"strange feeling" instead of "Your skin itches." if flags.beginner
is set) or by wearing a piece of junk (but uncursed) armour. These
two are more easily mitigated by being confused (fire sets light to
your hand, destroy armour makes a piece of armour glow purple and
potentially changes its rustproofing status), but the effects of
some of the others are more severe if you are confused.

Confuse monster confuses you if cursed; if you are confused, it
un-confuses you if blessed ("a red glow surrounds your head"), or
makes you more confused. Scare monster gives you "sad wailing" or
"maniacal laughter" (but, if cursed or confused, attracts
monsters). Teleportation will level teleport you if cursed or
confused (eep!). Gold detection detects traps if confused or cursed
- looking like gold, if cursed. Confused or cursed food detection
detects potions; the best way to handle this one is to ensure there
are some food items (and a potion, if it's not known uncursed)
around to be detected.

I think the best way to handle scrolls in this group is to
eliminate teleportation and then read them while confused and
wearing no rustproof armour. Failing that, wearing junk armour and
having no other inflammable items around may do the trick; but
teleportation can still blast you across the level (into a sticky
situation, naked.)

200 - create monster, taming, amnesia,
earth.

Amnesia must be identified somehow, making scrolls in this group
a prime candidate for whatever identifies you do have - but note,
above, that one can identify earth from Sokoban. Assuming that's
been done, earth does nothing in the endgame (other than on the
plane of Earth) or on the Rogue level, but creates at least one
boulder anywhere else regardless of b/u/c or confusion. If you
aren't equipped to deal with a potentially large number of
monsters, confused create monster creates acid blobs, which also
guarantees you will be able to see the results and so know what you
got. That leaves taming as the one that might do nothing visible
(but then you know what it is, anyway); interestingly, the effects
of taming cover a much wider area if confused. Wasting a scroll of
taming is irritating, but you have a 50% chance of identifying it
before amnesia anyway.

300 - genocide, punishment, charging, stinking
cloud.

Stinking cloud pays no attention to confusion, and always
identifies itself. Beware that the cloud's radius may be as large
as 4, if blessed; don't poison yourself.

Uncursed confused genocide will kill you very dead indeed.
Cursed confused genocide sends in 4-6 of your own role, which can
be nasty. Blessed confused genocide functions normally, which means
you can do confused testing of this group if you know the scroll is
blessed (but then you might as well just use it while
unconfused.)

Punishment is easy; if confused or blessed, "You feel guilty.",
and if you have a pickaxe or a pit to hand and a boulder, you can
ditch the iron ball in no time (arrange to push the boulder into
the pit while the ball is in it.)

I'm inclined to feel scrolls in this category are usually best
saved; a spare blessed charging spares you a wish on your first
WoW, and genocide is best used in pant-browning emergencies. Bless
'em and save 'em; when you find that WoW, you can always wipe out
liches if you happen to read genocide first.

The traditional method for identifying most wands is to engrave
with them after first writing something else with your fingers in
the dust; by and large, this either identifies the wand or gives a
message you can use to identify the wand. However, four wands give
no result; one group of three and one of two give identical
messages; and, if wands are found in a shop, you will be charged
usage fees for the charges you consume.

Light, enlightenment, create monster, digging, fire, lightning
and wishing will identify themselves immediately, as will secret
door detection if by some chance there is a secret door in the
room. Lightning blinds you while you are doing it - exercise
caution. The following wands give unique messages;

striking; "The wand unsuccessfully fights your attempt to
write!"

slow monster; "The bugs on the floor slow down!"

speed monster; "The bugs on the floor speed up!"

polymorph changes the engraving to a randomly selected
one.

magic missile; "The floor is riddled by bullet holes!"

cold; "A few ice cubes drop from the wand."

The following wands give no message; Nothing, undead turning,
opening, locking, probing, secret door detection (normally). If you
can be bothered, you can line up a locked door/chest, an unlocked
door/chest, a corpse, and a live monster; all these wands do
something to that lot, except nothing and secret door detection;
and nothing prompts for a direction where secret door detection
does not.

Death and sleep both give "The bugs on the floor stop moving!";
find some nice monster to volunteer for testing purposes (beware
bounces). The odds are ten to one that it's sleep (unless Orcus
dropped it).

Make invisible, teleportation and cancellation all cause the
previous engraving to vanish (actually, a teleported engraving is
elsewhere on the level, so if you find it you know which wand you
had), which is a bit awkward, especially as you can hardly zap them
at yourself.

Lining up a monster and a junk object does for this; if both
vanish, it's teleportation; if the monster vanishes, it's make
invisible. Alternatively, you can use a slow-moving monster, since
you can just nip across to its space and try to smack it if it
disappears - Raisse suggests a floating eye, because if it doesn't
disappear you had cancellation and you can kill it with impunity. A
third approach is to use an object that changes with cancellation -
if it goes away you had teleport, if it changes you cancelled it,
and otherwise you had make invisible. A fourth technique is to
stuff the wand into a spare bag of holding and see if it explodes -
although personally I find it hard to envisage a situation where
one would be that desperate to identify teleportation.

Price groups are included mostly for their utility when
shopping, and also because you can sort out some of the previous
differences with prices.

100 - light, nothing.

This lets you eliminate the wand of nothing from those others
that do nothing when engraved with (but the rest of them all cost
the same.)

There's a lot of wands in this group, and to make it more
irritating the 1/3 surcharge can confuse them with wands in the
next group but one; and you obtain wands so rarely that it's
unlikely you'll have more than one to try. However, you can pick
one of the 'engraving vanishes' wands out by price; make
invisible.

175 - fire, cold, sleep, lightning.

These wands are a good choice when shopping, because they are
readily identified, relatively inexpensive, and all deal
effectively with monsters.

200 - create monster, polymorph, cancellation,
teleportation.

Here's the other two 'vanishers'.

500 - wishing, death.

If you find one of these wands in a shop, you can line up the
shopkeeper (but not yourself on the rebound) and attempt to let
them have it. If it's death, fine; if it's wishing, wish for 2
blessed scrolls of charging and a wand of death, and let them have
it anyway. If you're not concerned about killing shopkeepers, this
is no bad plan, and it gives you about a 50% chance of netting a
wand of wishing.

Rings are difficult, because monsters never use them.
Conversely, you can always try on a non-cursed ring for one turn
and see if anything happens; the odds of (say) polymorph kicking in
during that one turn are very small. Don't try this next to a
powerful friendly (shopkeeper, say?) that will whip the snot out of
you if it's conflict; do try it next to a wussy peaceful monster,
or with several monsters in view next to each other. Do try to do
it when you have a wand of enlightenment to zap and see what
changed.

If you do not know the spell of "teleport away" and you are below
experience level 12 (8 for Wizards), press ^T while trying out an
uncursed ring. If it's teleportation, you will be told "You are not
able to teleport at will." rather than "You don't know that spell.";
this behaviour does seem to be intended.

The following rings will be identified by putting them on; see
invisible, if you are invisible and can't already see invisible;
invisibility, if not already invisible; adornment, gain
strength/constitution and protection, if not +0; and levitation, if
not levitating anyway. Some other rings - like conflict - can be
identified by observation of the effects and then #named
appropriately.

If you have two of a given ring, dropping one on a sink will
give a message that can identify the ring to you (you don't need
two, but since you usually lose the dropped one there's not a hell
of a lot of point otherwise); this is very effective one you have a
decent collection of rings. You will need to have a junk object on
the sink, in case the ring is hunger; and many of these effects do
not work, if blind.

These messages are as follows;

searching: "You thought your ring got lost in the sink,
but there it is!"
slow digestion: "The ring is regurgitated!"
[these are the two cases where you get the ring back]
levitation: "The sink quivers upwards for a moment."
poison resistance: "You smell rotten <fruit>."
aggravate monster: "Several flies buzz angrily around the sink."
shock resistance: "Static electricity surrounds the sink."
conflict: "You hear loud noises coming from the drain."
sustain ability: "The water flow seems fixed."
gain strength: "The water flow seems stronger/weaker now."
gain constitution: "The water flow seems lesser/greater now."
increase accuracy: "The water flow misses/hits the drain."
increase damage: "The water's force seems smaller/greater now."
hunger: "Suddenly, <junk object> vanishes from the sink!"
meat ring: "Several flies buzz around the sink."
[Effects from here demand that you are not blind.]
adornment: "The faucets flash brightly for a moment."
regeneration: "The sink looks as good as new."
invisibility: "You don't see anything happen to the sink."
free action: "You see the ring slide right down the drain!"
see invisible: "You see some air in the sink."
stealth: "The sink seems to blend into the floor for a moment."
fire resistance: "The hot water faucet flashes brightly for a moment."
cold resistance: "The cold water faucet flashes brightly for a moment."
prot. shape changers: "The sink looks nothing like a fountain."
protection: "The sink glows black/silver for a moment."
warning: "The sink glows white for a moment."
teleportation: "The sink momentarily vanishes."
teleport control: "The sink looks like it is being beamed aboard
somewhere."
polymorph: "The sink momentarily looks like a fountain."
polymorph control: "The sink momentarily looks like a
regularly erupting geyser."

That said, price grouping still has some value for rings; if you
can ID the real nasties in a group, you can try the rest on.

If only hunger wasn't in this group! Nothing else in here can
hurt you by being worn long-term even if cursed (although beware
the problem where you try on shape-changers in a shop and all the
mimics whip you), and some of them will easily identify themselves
to you.

[However, sustain ability can be awkward to identify - it's hard
to generate a stat change on demand. If uncursed, you can become
satiated, wait until the turn after you stop being satiated, eat
something with a known nutrition value, and see how long you are
satiated for - this lets you pick up on hunger.]

This risks confusion with the next group - but once you've got
aggravate monster out the way, you may as well wear noncursed rings
in this group (provided you didn't uncurse them - otherwise, there
you are with -3 uncursed increase damage...)

There's relatively few of these. The bad news is that they all cost
the same. The good news is that, provided you are not polymorphed,
trying on non-cursed amulets is pretty harmless. You might change
gender (which is irritating), fall asleep (do it in a controlled
environment) or be strangled (but then you just remove the amulet;
uncursed strangulation is not dangerous); but this is well worth it
for the possibility of donning life saving, and in any case these
harmful types are nearly always generated cursed. Again, the
wand of enlightenment technique is very useful here.

Of the non-harmful ones, ESP becomes known pretty well right
away. Reflection is bound to become obvious after a while. Magical
breathing can be tested for by stripping and jumping in a pool -
you'll crawl out, if it's not (beware; if you can teleport, you
often will, if not wearing AoMB). In theory you could also test for
magical breathing by overeating and seeing if you die, but this has
an obvious drawback. Versus poison is hard to identify
if you're already poison resistant, and life saving is hard to put
to the test (but you often find them round monsters' necks, the
standard way of IDing them - hence, an amulet dropped by an
intelligent necked monster is probably not life saving - but it's
not impossible.)

Of course, the 'plain' spellbook is blank paper, and the
'papyrus' spellbook is the Book of the Dead. Vlad's always contains
a spellbook of invisibility, and the Wizard will bring a spellbook
of dig to the Plane of Earth.

Any blessed spellbook can be read successfully, and any
spellbook granted you by your god will be blessed. Of course, there
is no guarantee that you can cast the resulting spell. :-)

The base price of a spellbook is always 100 times the spell's
level, making for easy identification of those one can safely read;
obviously, however, the surcharge can confuse a level 3 spell with
a level 4 spell.

The effect of reading a cursed spellbook is the same as that of
failing to comprehend an uncursed spellbook, so normally you need
to check cursedness before doing anything with a spellbook.

The question, then, is what level of uncursed spellbook you
can safely read. It's easy for wizards, who
receive a warning if they might not succeed, but the rest of us
have to chance it. The effects of a too-hard spellbook are very
severe, and I prefer to shop-ID the level of all spellbooks and
only read safe ones. You will fail to read a spellbook if a random
number between 1 and 20 is greater than (Intelligence + 4 + half XP
level - twice level of book); hence, you can only read safely if
this total is 20 or more.

Odd XP levels are useless for reading books; a level 3 character
is equivalent to a level 2 one (and a level 1 character might as
well be level 0). With that in mind, a level 0 character needs an
Int of 18 to read a level 1 spellbook safely. Every 2 XP levels
past that lowers the Int requirement by one, but each extra level
of the spell increases it by 2. The chance of failure is 5% for
each point of Int you are short. A moment's thought will reveal
that there's not much point in spellbooks unless you have a high
Int or a high XP level; at the high end of the spectrum, a level 7
spellbook requires an XP level of 24 to read safely even with Int
18.

That said, a low-level spellbook cannot paralyse you for very
long (but more than long enough for a cockatrice to stone you), but
although the worse spellbook aftereffects are generally seen at
higher spell levels, the 'teleport' effect is most likely at low
levels - a level 1 spellbook will give it every time - and being
*bamf*ed across the level when paralysed is a good way to get
killed. There is a sharp increase in paralysation times at spell
level 3 and above; levels 1 and 2 can only immobilise you for 1-3
turns at most, which you may be willing to chance, especially since
the probability of failure will be low. The particularly bold may
even want to try level 1/2 spellbooks of unknown cursedness.

Unless you have monstrous Int and XP level, or are a wizard,
reading unblessed books of unknown spell level is asking to be
killed.

These price groupings are pretty useless, to be frank; if you
identified every other spellbook in a group, you can probably read
the last one safely anyway.

There's not much to say about weapons, save that - like armour -
a shopkeeper will increase the base price by 10 zorkmids for every
point of positive enchantment. If you know the base prices for
every weapon and piece of armour (which I am not, no, going to list
here), you can easily determine which these are. Better yet, no
weapon or armour generated with positive enchantment is cursed;
just fling 'em down in a shop and pick up the expensive ones. Beware
items from bones piles!

If you have several stacks of objects that stack, like daggers
or arrows, the largest stack is probably uncursed +0.

Naturally, a named weapon (not found in bones) is always an
artifact weapon, which are occasionally randomly generated.

If a throwing weapon or piece of ammunition 'slips' or 'misfires'
when you throw or fire it, it is cursed; but cursed weapons and ammo
will not do this every time they are used. Exception; any greased item
may also slip or misfire.

Armour is much easier, since you can discover the +/- status just
by trying it on (once you know it's not cursed, and with the exception
of the autocursing types of headgear; of course, the enchantment
pricing technique above helps spot blessed armour); but there are a
few types of armour with shuffled descriptions. Positive enchantment
can obscure price groupings, but that's OK (again, apart from those
kinds of headgear) because such items are then always non-cursed and
can be removed (and as soon as you try it on and learn the + status
you know what group it's really in.)

Nearly all fumble boots, levitation boots, helms of opposite
alignment, and gauntlets of fumbling are generated cursed. Not all,
alas, so one may still get uncursed helms of opposite
alignment. Nevertheless, if you (as I do) #name a known cursed armour
item "cursed once plumed" or similar, and then find a second piece of
the same type also cursed, the odds are good that it is one of these;
conversely two noncursed items of the same type (without also finding
cursed ones) suggest that the item is not of this type (but if it's
not a helmet, you might as well just try it on.)

One type each of magical gloves (gauntlets of power) and boots
(kicking) is made of metal, not leather, and so rusts and corrodes
where the others burn and rot; this might be useful if found in a
bones pile or if you have spares and can change into a monster that
eats metal or leather. You might also try wearing non-cursed boots and
looking for changes in your spellcasting chances (a lack of a change
does not guarantee non-metallic boots - a full discussion of these
chances is beyond the score of this document). This is useless for
gauntlets of power, because they automatically ID when worn. Also, you
could immerse the item repeatedly and see if it rusts (or wear boots
and let a rust monster pound on you, I suppose). Beware; if your Luck
is high, many immersions may be needed.

If you use a stethoscope on monsters, you can gain a good idea
of the enchantment of their armour.

The most straightforward of these are the 'conical hats'; the
corunthaum and dunce cap. If you're not a wizard, you don't care;
if you are, you can either be prepared to uncurse the dunce cap
(not with the spell of remove curse), or use the fact that the base
cost of a corunthaum is 80 and that of a dunce cap is 1.

Next, the plain helmet, helm of brilliance, helm of telepathy,
and helm of opposite alignment - plumed, etched, crested and
visored. Plain helmets are cheaper (base cost 10 vs. 50), often
found on soldiers and minetown guards, and known to those classes
that start with knowledge of armour types, so that's pretty easy.
The other three are hard to tell apart, and opposite alignment
autocurses and blows away your divine protection; but, if you're
willing to take a chance on it, telepathy is pretty handy. (If one
of these helms doesn't do anything, it's most
likely +0 brilliance. Or you forgot to take off your amulet of ESP?
Or a +4 plain helmet...)

A 'slippery cloak' is always oilskin; a 'faded pall' is always
elven; an 'apron' is an alchemy smock. The cloaks with shuffled
descriptions are protection, invisibility, magic resistance and
displacement; the tattered cape, opera cloak, ornamental cope, and
piece of cloth. Protection and displacement both immediately ID
themselves when you wear them. If you're already invisible, it can be
hard to tell invisibility from magic resistance (if you have the HP,
zap yourself with a wand of magic missile or striking). It may be
sensible to try on these cloaks even if not known uncursed; they all
do useful things, and a cursed cloak only prevents you from changing
body armour (or shopping, if invisibility.) Note that protection and
displacement have a base cost of 50 where the other two have a base
cost of 60.

A polished silver shield is always reflection; if blind, it's a
'smooth shield'.

Four kinds of gloves are shuffled; leather (again, classes who
recognise armour get a bonus here), fumbling, power, and dexterity;
these are old, padded, riding and fencing gloves. It's hard to justify
trying these unless known uncursed; fumbling is awkward and +0
dexterity is useless. You can't tell +0 dex from leather if you don't
already know leather, which is a nuisance. Gauntlets of power are made
of metal. Leather is very much cheaper; base cost 8 versus 50 for the
others. Guards and soldiers, again, often have leather gloves.

Boots are pretty awkward, because there are many types. 'Walking
shoes', 'hard shoes' and 'jackboots' are just low boots, iron shoes
and high boots, respectively. However; speed, water walking,
jumping, elven, kicking, fumble and levitation boots are shuffled
into jungle, combat, hiking, mud, buckled, riding and snow
boots.

Elven and kicking boots are cheap, with a base cost of 8. Fumble
and levitation boots cost 30 (and are nearly always cursed), and
the others 50. Since fumble are the only harmful kind (and the cost
50 boots do their job just as well if cursed), this can be
useful.

Elven monsters are very likely to start with elven boots.

Levitation, elven and speed boots ID themselves right away, unless
you are already levitating, stealthy or very fast; not being stealthy
can be hard to arrange, though. Jumping boots can be trivially
identified by trying to jump; fumble boots (uncursed, I hope) by
wandering around in them.

Kicking and water walking boots are more difficult. Kicking boots
may be distinguished because of the fact that you will always kick
down doors when wearing them (if you have a lot of doors to spare -
obviously, you can never be quite sure), but a more straightforward
method if you are not a monk, samurai or sasquatch is to kick any
object with and without the boots on; with kicking boots on it will
move between 1-3 further spaces. Kicking ranges are also increased on
ice, so don't compare on-ice with off-ice ranges. Monks, samurai and
sasquatches can still try kicking doors, but they are quite likely to
kick down doors anyway. As mentioned above, jumping into pools IDs
water walking right away, and will also sort out kicking boots when
they rust.

There is relatively little potential for confusion amongst
tools, but there are a few complicated types, and the question of
whether the tool you have is cursed is always interesting.

4 objects are described as 'bag'; the sack, oilskin sack, bag of
holding, and bag of tricks. The sack is considerably cheaper (2 vs.
100), and you may well start with one; the bag of tricks is trivially
identified by #looting or applying it (be equipped to handle the
results. #looting will do at most 10 damage, where applying may summon
an arbitarily nasty nasty and will cause a shopkeeper to charge you
for that use, if it's not your bag.) The other two can be sorted out
by finding a bunch of junk objects (rocks, say) that just make one
Burdened and stuffing them into the bag; if you aren't Burdened, it
was holding. Take them out, drop two (now un-Burdened), and put them
back in; if you are Burdened, it's cursed holding. If objects
disappear upon applying, it's cursed holding, and you want to take out
all the remaining objects now. Use #name appropriately.

If you find a bag in a bones pile, it is mostly likely cursed
and full of juicy loot. You don't want to chance its being holding
(and losing half the loot), so if you can lift it at all, it's
probably a good idea to uncurse it first; if not, clear other
objects away and give it a zap of cancellation (if possible) - this
doesn't harm the contents. It's not clear to me that cursed holding
can be generated outside of a bones pile.

Another way to sort out the bags which are not tricks is to put
water-damageable objects such as junk potions and scrolls into them
(be sure it's not cursed holding, but since holding's easy this is
best for oilskin sacks and plain sacks in the absence of price-ID) and
immersing it repeatedly, checking to see if the contents are damaged.
With high Luck you may require many immersions.

There are two objects called 'lamp'; the oil lamp and magic
lamp. Oil is cheaper (cost 10 vs. 50), and magic is inexhaustible -
either kind may 'splutter' and fail to light if cursed. Four
approaches; check the price, bless one and try #rubbing it, just
light the first you find and see if it ever gets used up, or try to
refill it with a potion of oil (but you might as well wait and see
if it gets exhausted, unless you have 2 kinds of lamp and want to
know which is which right away). Regardless, it's worth #naming the
first lamp you find 'lamp 1' or something, so you can tell if
you've actually got both flavours.

There are two 'whistles'; tin and magic. Apply them; a high
whistling noise is tin and strange is magic. Easy. You may not need
to #name magic, if you have a pet to be summoned. (These objects
are unlikely to be cursed, but 'high-pitched humming' is magic,
'shrill' is tin.)

For all musical instruments, you should improvise unless you are
trying to open the Castle drawbridge (not that you get a choice
with drums).

Two 'flutes'; magic and wooden. Magic flutes, if charged,
produce 'soft music' (and put monsters to sleep); if not, they are
like wooden flutes - they 'trill' or 'toot' (and charm snakes, in
the former case, which is likely if you have good Dex or XP level).
However, magic flutes are never generated uncharged, so this should
not normally be an issue.

Four 'horns'; tooled, frost, fire and plenty. Frost and fire ask
for a direction (same issue that an uncharged one is like a tooled
horn); a horn of plenty makes food (an uncharged one does nothing,
but it's the only horn that does, so you know what it is.) Beware;
tooled horns awaken monsters.

Two 'harps'; magic and wooden. With the usual proviso about the
uncharged magic version looking like a normal one, the magic harp
produces 'very attractive music' (and charms monsters) and the
normal one 'produces a lilting melody' or 'twangs' (and charms
nymphs, in the former case.)

Two 'drums'; leather and earthquake. If charged, it's not hard
to work out which one you have.

All bells and bugles are normal, except the 'silver' Bell of
Opening.

Various tools are easily identified, but you may be unsure as to
their cursedness status (although, as mentioned above, only light
sources, grease, crystal balls and figurines will normally be
generated cursed). With a cursed camera, you will photograph yourself
half the time. A cursed towel or blindfold cannot be removed, and
(a)pplying a cursed towel covers you in gunk (useful in emergencies if
you have no other way of blinding yourself). A cursed stethoscope may
well cause you to hear "your heart beat" (even if you are polymorphed
into a heartless monster, alas). A cursed leash will strangle your pet
- potentially fatally. A cursed mirror will fog up and not
reflect. Cursed bells summon nymphs; the cursed Bell of Opening
summons undead. Cursed tinning kits make cursed tins. A cursed unicorn
horn gives you one of several nasty conditions, potentially
fatally. Cursed grease greases your hands. Cursed land mines and bear
traps tend to go off on you. Wax candles burn for 400 turns where
tallow candles burn for only 200, so if you have some obscure need to
identify candles (perhaps to eat wax candles without breaking
vegetarian conduct) you could light one, wait for it to burn down, and
#name others that stacked with it. That's about all the interesting
ones.

Rocks are technically 'gems', as are gray stones. Gray stones come
in four flavours; flint stones, luckstones, touchstones and
loadstones. They can be price-IDed; luckstones have a base value of
60, touchstones of 45; the other two are worthless. Loadstones are
always generated cursed; other gems, uncursed, so apart from bones
files you need not fear carrying around a cursed luckstone.

You can only kick a loadstone across the floor if your Strength is
at least 22 and you are either wearing kicking boots or are a samurai,
monk or sasquatch; even then you will not move it reliably. If you are
on ice, an extra 1-3 is added to all kicking ranges (which might
otherwise be negative); if you can kick a gray stone on ice, it's best
to kick it to a non-ice space before deducing anything. A gray stone
that cannot be kicked owing to an awkward position presents a
difficulty; so does one in a chest or box. If you can, you can try
locking the box and #forcing it with a blunt implement to destroy the
box; but if you break the lock, you are out of luck unless you have
the spell of wizard lock or a wand of locking. If you have the
patience you could count up your total weight and arrange matters so
that the weight of the box and a loadstone would take you to a
different burdening status to that produced by the box and a harmless
stone. If you can afford to uncurse the thing, you can always pick it
up and see if it's really heavy; remember to #name it before dropping
it again if it is a loadstone. To my knowledge, there's no way to
#name a loadstone without picking it up, so even if you kick-test one
you've got no way of marking it unless you have holy water to
burn.

Touchstones are easily identified provided you're not blind; #rub
any unknown gray stone on a hard object that is not gold, silver or
wood, like an iron weapon. If it's a touchstone, you will hear
"scritch, scritch". Once you have a blessed touchstone - uncursed if
you are a gnome or an archaeologist, the latter of which begin with a
touchstone - you may rub it on any gem or stone to identify it, which
certainly helps with the other gray stones.

As for flint and luckstones, #name any gray stones you can't
kick-test or determine are touchstones by #rubbing; once you have two
flavours, you know you have a luckstone. Alternatively, only flint
stones and touchstones are generated in piles of more than one; you may use
enlightenment to tell that there is a luckstone in your inventory (you
will always have "extra luck" or "reduced luck"); or see the
discussion of the guaranteed items in the Mines below.

Gems come in two flavours; soft and hard. You can engrave in the
floor with hard gems, but only write in the dust with soft ones.
All hard gems are valuable (but not all soft gems are worthless).
This provides sufficient information for most purposes; you don't
need every valuable gem to get all a shopkeeper's goodies (but you
_will_ need scrolls of identify to actually ID your valuable gems
and sell them) or to get luck out of unicorns. If you are interested
in IDing gems at all, this is the technique that reveals the maximum
information for the minimum amount of effort.

You can identify amethysts with the trick in the 'potions'
section.

A second way to identify classes of gems is by flinging them to
unicorns. This also has an effect on your luck - however, it's
equally likely to be negative as positive if the unicorn is not
coaligned, so best to stick to coaligned unicorns. The unicorn
keeps the gem if it's valuable and you haven't #named it, so I
usually #name the target gem 'valuable red' and fling it; if I get
it back, I can then #name it 'worthless red'. If it's not #named,
the unicorn 'graciously' accepts glass, and you need another one to
actually #name.

Glass golems, when killed, create worthless glass but not
valuable gems. I should add a disclaimer here; I've never seen a
glass golem drop anything, and I don't see why one shouldn't happen
to be carrying a valuable gem, which might confuse the issue.

The gems in the 4 corners of Fort Ludious are always diamonds,
emeralds, rubies and amethysts. In 3.4 the Gnomish Mine bottom has
become considerably more complicated, alas. There are three randomly
selected endings, two of which have layouts from familiar versions of
NetHack. Portions of these next paragraphs are quoted directly from
Dylan's Dungeon Gazetteer.

In general, each gem or piece of glass (or flint or touchstone)
listed below may become a pile of 2 at
generation time, with a 1/6 chance.

The first of these is "the Mimic of the Mines", a variation on the
only mine ending in still older versions of NetHack; this is the
ending where you descend into an irregularly shaped area which is
dark. There are seven awkward or secret spots on this level, six of
which (randomly assigned) will contain;

A worthless piece of violet glass, an emerald, a diamond, and a mimic
imitating a luckstone.

An amethyst, a worthless piece of green glass, a diamond, and a mimic
imitating a flint stone.

An amethyst, an emerald, a worthless piece of white glass, and a mimic
imitating a loadstone.

A worthless piece of violet glass, an emerald, a worthless piece of white
glass, and a mimic imitating a touchstone.

A loadstone, a ruby, and a worthless piece of red glass.

A luckstone, a worthless piece of red glass, and a ruby.

The good news is that all but two of the spots are kickable, so it is
highly unlikely that you will be unable to sort out the loadstone from
the luckstone. If you can tell some of the various worthless gems from
their valuable cousins, you might be able to differentiate some of the
stacks by the initial ordering of items and hence make some more
identifications.

The second ending is the Gnome King's Wine Cellar; in this one you
start in a wide short lit rectangular room with a single doorway in
the right-hand wall. Here the gems are in a 2x2 rectangular hole in
the rock you can dig out; this contains at least two diamonds, two
random gems (NW); two emeralds, two random gems (NE); one ruby, one
emerald, two random gems (SW); two amethysts, one ruby, one random
gem, and a luckstone on top (SE). Often the random gems will not
interfere with colour-based ID of the valuable ones; if you find two
gray stones in the south-east pile, the top one is the luckstone (but
kick it off anyway out of paranoia?)

The new ending is the Catacombs, where you begin in a lit square
room with only secret entrances. Randomly placed on the level are two
diamonds, three emeralds, two rubies, and two amethysts; and there are
three secret spots - one empty, one with a level teleport trap and a
luckstone, and one with a level teleport trap and a flintstone.
Getting the stones off the traps is left as an exercise for the
reader.

Gem pricing in shops is curiously complicated. Selling prices
(where the gem is un-IDed) leak a little information in a way I still
believe is an inadvertently possible abuse, and hence I am not going
to document this - especially since any compilation option that
changes object ID numbers will invalidate the whole list. However, the
buying price of each worthless gem is randomly set (each game, not
each gem or each purchase) to that of one of two valuable gems of the
same colour; hence if you find a soft gem of a given colour with a
price that does not match one of the possible worthless glass prices,
you know it is still valuable - in particular, the dilithium crystal
qualifies here and sometimes the various variable-colour gems (see
below). The table below has a '*' next to the name of all gems that
have a duplicate price for worthless glass.

Colour grouping can help sort out gems - unfortunately, various gem
colours are shuffled at game start time, to make our lives
miserable. The table below indicates the chance that the listed
gem is of the listed colour (but a given gem will always be the same
colour in a particular game - if one turquoise is green, they all
are.)